Field of the Invention
The present invention relates to an agricultural machine for the harvesting of plants, in particular of fodder, this machine being movable in a direction of advance and comprising in particular:                a chassis,        at least one support arm articulated on the chassis and movable with respect to the chassis between work configuration in which the support arm extends laterally with respect to the chassis, and a transport configuration in which the support arm is folded such that its overall dimension perpendicularly to the direction of advance (A) is reduced,        at least one work tool comprising an inner lateral end and an outer lateral end, and being able to occupy at least one work position in which the work tool acts on plants lying on the ground, and at least another position,        a connecting device, by means of which a frame of the work tool is connected to the support arm, this connecting device allowing at least when the support arm is in the work configuration, a first movement of the work tool with respect to the support arm during which the inner lateral end and the outer lateral end of the work tool move vertically with respect to the support arm and in the same vertical direction with respect thereto.        
Discussion of the Background
A machine of this type is known from the document U.S. Pat. No. 8,186,138 B2. This machine is of the type known under the name of “Merger”. This machine comprises a chassis designed to be hitched to the rear of a tractor and supported on the ground by wheels in its rear part. On at least one lateral side of the chassis a support arm, carrying a work tool, is articulated. This support arm can be placed in a work configuration in which the work tool extends perpendicularly to the direction of advance and substantially horizontally. The work tool comprises a toothed rotor which, during work, extends perpendicularly to the direction of advance and picks up the plants lying on the ground. The picked up plants are moved towards the rear by the rotor, in the direction of a belt conveyor which moves the plants perpendicularly to the direction of advance, in the direction of a lateral side of the work tool. On the known machine, the work tool is, in its rear part, connected to a support by means of an axis oriented horizontally and parallel to the direction of advance when the support arm is in the work configuration. This support is, in its turn, connected to the support arm by means of a first connecting-rod and a second connecting-rod situated beneath the first connecting-rod. At each of its ends, the first connecting-rod is articulated on the support arm and on the support by means of respective physical axes which are oriented horizontally and transversely to the direction of advance when the support arm is in its work configuration. The result of this arrangement is that the first and second connecting-rods can move vertically with respect to the support arm in the work configuration, such that the work tool can, in its entirety, move upwards or downwards to follow a terrain having an uneven profile. However, this movement is solely vertical. The support arm being in the work configuration, the distance, measured horizontally and perpendicularly to the direction of advance, which separates the work tool from the chassis, remains constant. During the harvesting period, the plants can, following their mowing, be grouped together in windrows, the width and the spacing of which with respect to one another vary according to the mowers and/or windrowers which are used. One case of use of the known machine consists in that the tractor and the machine straddle a first windrow, such that this first windrow passes between the wheels of the tractor and between the wheels of the machine, and in that the work tool picks up a second windrow parallel to the first windrow and placed on a lateral side of the tractor. This second windrow is deposited by the machine on or along the first windrow, or on or along a third windrow parallel to the second windrow and placed at a greater distance from the first windrow. In such a case of use, the path of the tractor and of the machine is forced by the fact that their respective wheels must not crush the first windrow. It may therefore occur that depending on the width of the second windrow and the distance which separates it from the first windrow, this second windrow is only taken up partially by the work tool. The latter therefore leaves a portion of the second windrow which is not picked up. A complete picking up the second windrow therefore requires an additional passage of the machine, which increases the time spent in the field and the operating costs, and reduces productivity. In addition, the fact with regard to the work tool of separating the second windrow into two parts increases the risk of jamming of plants within the work tool. Furthermore, the manner in which the second windrow is redeposited on or along the first or the third windrow cannot be modified, because it is forced by the distance separating the work tool from the chassis, the wheels of which straddle the first windrow. Consequently, the shape of the new windrow, obtained by the regrouping of the second windrow and of the first or of the third windrow, is not always optimal according to the nature of the plants and the meteorological conditions which are encountered. Finally, the known machine does not allow the transverse positioning of the work tool to be modified with respect to the tractor. Consequently, it is in particular not possible to adjust the total width of the tractor/machine assembly during work.
Another machine known from the document WO 2011/112077 is in accordance with the preamble of claim 1. On this machine, the work tool is connected to the concerned support arm by means of a connecting device including a first arm and a second arm. The first arm extends substantially in the direction of advance, from a first vertical articulation axis to the support arm. At its end remote from the first axis, the first arm carries a second arm by means of a second articulation axis extending substantially in the direction of advance. This second arm extends transversely to the direction of advance and carries, at its end remote from the second axis, the frame of the concerned work tool. By pivoting of the second arm about the second axis, the work tool can move vertically. Furthermore, the second arm is telescopic so as to enable a transverse movement of the work tool. This connecting device is complex and cumbersome due to the first and second arms which extend different respective directions. In particular, the telescopic arrangement of the second arm is complicated and expensive. Finally, during work, the second articulation axis is subjected to considerable mechanical stresses. These originate on one hand from the vertical movement of the second arm with respect to the first. On another hand, the forces which the plants moved by the machine advancing in the field exert on the work tool generate a torsion torque about a vertical axis passing through the second articulation axis. This torque is high owing to the great length of the transversely directed second arm, which can give rise to a rapid wear of the second axis.